1. Field of the Invention
The present invention relates to chain tensioning devices, and more particularly pertains to chain tensioning device for use in tensioning endless loop sprocket driven chains. Frequently, in industrial machinery, chains in chain drive systems become loose due to stretching of the chains. In order to compensate for the stretching, the chains must be tensioned. Prior art chain tensioning methods include the installation of idler sprockets, which require a mounting surface adjacent the chain drive, or the removal of links from the chain. In many instances, the amount of additional chain tension required is less than that obtained by removing a single chain link. In order to overcome this problem, the present invention provides an inexpensive and easily installed chain tensioning device.
2. Description of the Prior Art
Various types of chain tensioning devices are known in the prior art. A typical example of such a chain tensioning device is to be found in U.S. Pat. No. 2,766,634, which issued to M. Frank on Oct. 16, 1956. This patent discloses a bumper pad for engagement with an endless loop sprocket driven chain. A synthetic rubber chain engaging pad is mounted on a bracket which requires a mounting surface adjacent the chain to be tensioned. U.S. Pat. No. 3,707,092, which issued to F. Piech on Dec. 26, 1972, discloses a drive chain which is tensioned by rollers and abutment pads. U.S. Pat. No. 4,193,314, which issued to T. Horner et al on Mar. 18, 1980, discloses an engine timing chain snubber which includes a pair of guide shoes supported on the engine block and extending in non deflecting contact with the inner sides of unsupported chain portions between drive and driven sprockets. The guide shoes prevent movement of the chain runs inwardly of their tensioned position and thus prevent chain oscillation or vibration. U.S. Pat. No. 4,492,304, which issued to R. Geis on Jan. 8, 1985, discloses a retainer for preventing a conveyor drive chain from jumping off its sprocket. The retainer comprises a shoe having a lining with an arcuate working surface of anti-friction material disposed over a lower run portion of the chain adjacent a drive sprocket. Coiled springs bias the lining into engagement with the drive chain. U.S. Pat. No. 4,530,681, which issued to N. Kurata et al on July 23, 1985, discloses a mechanism for tensioning a motorcyle engine cam chain. The mechanism includes a guide on the slack side of the chain which is controlled by two spaced pivotally mounted links. One of the two links is biased by a spring to tension the cam chain.
While the above mentioned devices are suited for their intended usage, none of these devices disclose a mechanism which may be easily and quickly installed on an existing endless belt chain without requiring attachment to any adjacent supporting surfaces. Additionally, none of the aforesaid devices disclose the use of a chain tensioning device which includes an automatic chain oiler. Inasmuch as the art is relatively crowded with respect of these various types of chain tensioning devices, it can be appreciated that there is a continuing need for and interest in improvements to such chain tensioning devices, and in this respect, the present invention addresses this need and interest.